Hi,
To find out if you have a warrant depends almost entirely on state law. If I wanted to find out if I had a warrant, I might ask a cop friend to run me, but I realize that might not be workable for you. There are commercial services available that will supposedly check for warrants, but I'm not sure they can really be conclusive.
A warrant for your arrest would be issued by a court somewhere; warrants aren't issued by the police.
So here's my best idea for you: you probably have a pretty good idea of where the warrant would have come from. For example, if you think it's possible the Columbus, Ohio police are "after" you (or someone you're interested in searching), then a very good idea is to contact any court that would issue warrants out of that location. I know from past searching experience that that would almost always be Franklin County Municipal Court. So obtain the phone number for their "file room" (sometimes called a records room) and ask them what they can do with your name or other information. You can get all this information from your local phonebook or from a site like
Superpages.com
This way you don't have to go anywhere in person, which I certainly understand may be something you don't much want to do right now. :)
I want to point out though, this is only going to be about 90% (my estimate) effective, because there frankly is a mess of courts out there, many having full or partially overlapping jurisdictions. But most of the time that is only marginal. If it's an "everyday" underlying crime or whatever that you're curious about, this is a pretty good way to check.
Now, if you know what specific case the trouble might be coming from, there's happily a quick way you can usually end this. Simply go to the court site associated with that case and look at the online case docket for that case. That information screen is virtually always going to say if a warrant was issued for the defendant. In fact, if you end up calling the court, as outlined above, you generally just need to ask the guy on the phone to look toward the end of the case file and tell you if a warrant was ever issued.
I hope this helps you out.